1. Field of the Invention
This invention relates to the field of microcircuitry chip components. More particularly, it relates to a method of and an apparatus for packaging said components in specific orientation within a carrier tape. Such a tape provides efficient and safe handling and transportation as well as speed and accuracy in unpacking and later placement of the components on an electronic circuit board.
2. Description of the Prior Art
In recent past, there has been substantial development in the fabrication of circuit boards used in various electronic devices such as computers. While previously, microcircuit components had been attached to a circuit board by inserting their connecting wires through small holes in the board and soldering them to conductor leads, many chip components are now fabricated such that they can be directly soldered to the circuit board free of any wires or other elongated connectors.
Components such as capacitors, resistors, diodes, chip form LEDs, multilayer inductors in chip form, small outline transistors (SOT's) and film capacitors are now fabricated in chip form with a metal band about each end thereof that is smooth and planar to the body thus enabling them to be laid flat on the circuit board and soldered thereto. By this means, the time consumed in inserting the wires through the holes and thereafter heating and soldering them to the connectors is eliminated. Also, unwanted electrical resistance from poor heating, flaws in the connection wires and oil from human contact are eliminated so that the speed at which these devices is handled is greatly reduced thus increasing productivity.
These chip components may vary in size from a length of about 0.080 inches to 0.240 inches (2 mm to 6 mm), a width of about 0.040 inches to 0.120 inches (1 mm to 3 mm) and a thickness of about 0.010 inches to 0.080 inches (0.25 mm to 2 mm). In many instances the attachment bands completely encircle the component body so that they are attachable along both flattened faces thereof.
It is known in the art to deal with small items by packaging and storing them between the mating surfaces of elongated strips of tape, see U.S. Pat. No. 2,885,849. In some cases, one or both of the tapes may undergo a preliminary embossing operation that creates a series of pockets or embossments spaced along the tape into which the small item or component may be sealed with a flat cover tape, see U.S. Pat. No. 3,284,984.
To date, the prior art has either loaded these small items into the tape by dropping them out of a hopper onto the tape and into the embossments, see U.S. Pat. No. 3,846,956 or by having a suction nozzle pick up each item, one at a time, from a source and transfer it to the embossment area where the vacuum is released and the item dropped into the embossment. In the first method, there is no practical way to control orientation of the items in the embossments and, by random action, they will take on mixed orientations, some being aligned lengthwise with the tape and some transverse thereto. In addition, severe vibration of these components may cause cracks to develop in their ceramic substrate or denting or scratching of the ceramic face or metal bands that will alter their electronic characteristics and cause damage or loss of quality to the circuit board.
In the second method, significant real time is consumed in picking up, transporting and setting down the item so that productivity is greatly limited. It is necessary for achieving low fabrication costs of electronic circuit boards that the chip components be rapidly loaded into a carrier tape in specific orientation so that during fabrication they may be rapidly unloaded and conveniently placed directly onto the circuit board for attachment thereto without the necessity of turning or rotating them. It is further necessary that the carrier tape be totally and completely filled with chip components. With the large amount of components used in each circuit board and the high speed automation employed in placing each one in a specific location for connection, each empty carrier embossment represents lost machine fabrication time and possibly further time-consuming assembly involving costly hand operations. To date, maximum loading rates of specifically oriented microchip components into an embossment-type carrier tape is achieved by use of the vacuum nozzle method, previously described, with obtainable rates in the area of 10,000 to 30,000 loadings per hour.